The Society for the Protection of Unborn Children, a lobby group opposed to abortion rights, says the teaching of equal marriage in schools would lead to the “promotion” of gay lifestyles.

Anthony Ozimic, a member of the society, made the comments last week on ITV’s This Morning programme, during a discussion about the government’s equal marriage plans for England and Wales.

He claimed allowing schools to teach their students about the topic will “confuse and mislead children about the nature and meaning of sexuality,” and that marriage has always been “heterosexual”.

Mr Ozimic claimed that schools risk being “forced to teach something which is not actually true.”

When presenter Holly Willoughby remarked on the changing nature of human rights throughout the centuries, Mr Ozimic responded by saying: “Some things change and some things stay the same, and really the core of marriage has always been between a man and a woman open to childbearing, which is not something that applies to same-sex couples.”

Mr Ozimic described same-sex marriage as a “category error” and that homosexuality is “not natural” and said “homosexuals are promiscuous”.

In response to the interview, a Department for Education spokesperson said: “The government’s proposals for equal marriage do not change anything about teaching in schools.

“Teachers will continue to be able to express their own personal beliefs about marriage.

“Schools have a requirement to ensure they do not teach anything that would be considered inappropriate to a pupil’s age, religious or cultural background and they must ensure pupils are presented with balanced, factual information about the nature and importance of marriage for family life and bringing up children.”